Body builders and other weight training enthusiasts often find it difficult to perform weight training exercises which isolate certain muscles of the lower extremity. A preferred way for achieving muscle balance in the lower extremity and/or strengthen certain leg muscles which may have atrophied after an accident or injury is by working isolated muscles or muscle groups through a series of controlled leg exercises. A problem arises when a person only has access to conventional weight training equipment which is found in gyms, spas or the home, since it is often inconvenient and sometimes even dangerous to modify conventional weight training equipment for specialized use in the isolated strengthening of the hamstrings, quadriceps, calves, etc.
There are disclosed in the prior art various forms of leg exercise devices which are directed to attaching weights to an ankle boot worn by the user. The goal of these devices is to increase muscular effort by adding weight so that muscular development in certain muscles is enhanced. These prior art leg attachment devices suffer from many defects in that they are: uncomfortable to wear; difficult to use; require the use of specialized, non-standard weights; or suffer from a combination of all the above defects.
U.S. Pat No. 2,952,459 (Moffit) discloses a leg exercise devise comprising a brace which is circumferentially strapped to the leg just below the knee and includes a pair of elongated bars, which during use, are vertically disposed to lay against the inside and outside of the leg. Specially shaped weights are attached to the bars by means of a groove provided to each weight, which groove is adapted to slidingly engage the edge portions of each elongated bar. U.S. Pat. No. 4,838,546 (Winston) teaches to provide a wrap-around fabric ankle strap having a plurality of elongated pockets, each of which are adapted to receive one or more specially shaped cylindrical weights. Both Moffit and Winston require special, limited use weights which are used only in combination with their respective leg exercise devices. Further, neither Moffit n or Winston suggest or teach to provide any means for preventing their leg exercise devices from moving up or down the user's shin or twisting about the user's leg or ankle which tends to occur during a swinging leg movement.
U.S. Pat. No. 4,911,434 (Herring) discloses a weight apparatus for exercising which comprises a pair of ankle cuffs which are interconnected by a weight supporting strap. In use, the strap is disconnectable from either ankle cuff and is disposed to support conventional disc-shaped weights. This is accomplished by threading a disconnected strap end through the conventional weights bar-receiving hole provided in the center portion of each disc-shaped weight, and then reconnecting that strap end to its respective (other) weight cuff. This apparatus is directed to adding a single, dead weight load to both legs simultaneously to perform various weight training exercises involving both the upper and lower body. It is not well suited for the exercises of a single leg in view of the dual ankle cuff and interconnecting strap arrangement. Indeed, it would be extremely difficult to perform isolated muscle exercises of one leg independent of the other leg, even if one ankle cuff was disconnected from the strap. Also, since the attached weights are permitted some degree of swingable movement, there exists the potential for user injury, for example, a moving weight hitting the user's leg.
Another leg exercise device which permits adjustment of the weight load resistance over a continuous range is disclosed in U.S. Pat. No. 4,896,879 (Klawiter) wherein an L-shaped, liquid (or sand) fillable container is strapped to the user's foot. To vary the resistance load of this leg exercise device, the user must first remove the device from his or her foot in order to add fluid to, or remove fluid from, the container. The user is also exposed to the risk of fluid spillage when attempting to vary the fluid volume of the container. Over time, repeated fluid spillage will tend to damage the padding and straps associated with the device. A further disadvantage with this device is that when the fillable volume is only partially filled, the weight tends to shift when the device is lifted. Also, the maximum weight load is limited by the total volume of the container.
It is also known from the prior art to provide a padded ankle boot having a hook disposed on a forward facing surface or shin covering which is adapted for receiving a fixed horizontal bar. These boots are well known in the art as "inversion boots", and are intended for use in suspending a human in an inverted posture from a fixed support, such as a horizontal bar. Examples of inversion boots include U.S. Pat. No. 4,497,314 (Miller); U.S. Pat No. 4,523,582 (Barber); U.S. Pat No. 4,515,512 (Teeter); and Des. 267,343 (Miller et al). None of these patent documents teach to adapt the hook portion of the inversion boot to accept the attachment of conventional weights in order to perform isolation exercises for the lower extremity while the user is in an upright position.
There is a definite need in the art for a leg exercise and rehabilitation device which includes means for the attachment of conventional, readily available weights to a boot member worn by the user. There is also a need in the art for such an exercise device wherein the boot is securely and adjustably mountable on the user's ankle region and includes an additional strap for preventing torsional movement of the boot (and the attached weight) about the user's ankle region. Further, there is a need for such a leg exercise device which is easy to use, comfortable to wear and is inexpensive to manufacture.